<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>清空清除</title>
    <script src="js/jquery/jquery-3.3.1.min.js"></script>
    <style>
        #city{
            background-color: lightblue;
        }
        #food{
            background-color: lightpink;
        }
    </style>
    <script>
        $(function (){
            $("#btn1").click(function (){
                $("#city").remove();
            });
            $("#btn2").click(function (){
                $("#food").empty();
            });
            // insertAfter()
            // insertBefore
        });
    </script>
</head>
<body>
<ul id="city">
    <li id="bj">北京</li>
    <li id="tj">天津</li>
    <li>重庆</li>
    <li>南京</li>
    <li>济南</li>
</ul>
<ul id="food">
    <li>把子肉</li>
    <li>火锅</li>
    <li id="ky">烤鸭</li>
    <li>小笼包</li>
    <li id="gbl">狗不理</li>
</ul>
<button id="btn1">移除元素ul city</button><button id="btn2">清空元素ul food</button>
</body>
</html>